There are some possible solutions floating around. See one example below. It seems like enough of a problem that Apple might provide a user-agent fix in an iOS13 update, but in the meantime a workaround like this might suffice.
[quote]As for me, the most simple way to detect iOS / iPad OS device now:
let isIOS = /iPad|iPhone|iPod/.test(navigator.platform) ||
(navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1)
The first condition is old-fashioned and works with previous versions, while the second condition works for iPad OS 13 which now identifies itself as “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15) AppleWebKit/605.1.15 (KHTML, like Gecko)”, which by all platform detectors I know is not detected (for now) neither as mobile nor desktop.